US4653854A - Cellular reflex-reflecting sheeting - Google Patents

Cellular reflex-reflecting sheeting Download PDF

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US4653854A
US4653854A US06/708,253 US70825385A US4653854A US 4653854 A US4653854 A US 4653854A US 70825385 A US70825385 A US 70825385A US 4653854 A US4653854 A US 4653854A
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support film
reflex
sheeting
film
reflecting
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Nobuhiro Miyata
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Seibu Polymer Kasei KK
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Seibu Polymer Kasei KK
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/12—Reflex reflectors
    • G02B5/126—Reflex reflectors including curved refracting surface
    • G02B5/128—Reflex reflectors including curved refracting surface transparent spheres being embedded in matrix

Definitions

  • This invention relates to improvements over the structure of reflex-reflecting sheeting of a type having on the surface of the sheeting many isolated small compartments which are respectively hermetically sealed in the form of cells.
  • a reflex-reflecting sheeting which retroreflects the incident light in the direction of incidence is widely used for various purposes including traffic signs and automobile number plates.
  • One of factors determining desirable reflex-reflecting properties of the reflex-reflecting sheeting is angle characteristic. As the angle of incidence to the surface of the sheeting increases, the amount of reflex-reflecting light against the amount of the incident light tends to decrease. It is desirable in the reflex-reflecting sheeting that the rate of this decrease in the reflex-reflecting light should be small, that is, the angle characteristic should be good.
  • This transparent focus layer 3 should desirably be coated in a uniform thickness such that it will form a partially spherical contour concentric with the glass beads. If, for example, the thickness of the focus layer 3 in the direction in which the incident light a having the angle of incidence of -4° C. is incident is such that the incident light focuses upon the metallized layer 4 whereas the thickness of the layer 3 in the direction in which the incident light b having the angle of incidence of 30° is incident is greater than that, the incident light b focuses at a point inside the layer 3 and is reflected as diffused light from the metallized layer 4, whereby the angle characteristic of reflex-reflection is deteriorated.
  • the focus layer 3 is a thin layer of about 10-20 ⁇ m which is normally formed by coating of a solvent-type coating, the surface of the coating material tends to become flat due to surface tension thereby making it extremely difficult to form the surface of the layer 3 contacting the metallized layer 4 into a partially spherical contour concentric with the glass beads.
  • the capsule type reflex-reflecting sheeting is of a structure in which, as shown in FIGS. 2 and 3, a metallized layer 4 is provided directly on the lower hemispheres of glass beads 2 which are disposed in spaced relation below a transparent protective film 1 with isolated hermetically sealed small cells 7 being formed between the glass beads 2 and the protective film 1, and a support film 5 underlying the metallized layer and having the lower hemispheres of the glass beads 2 embedded in the upper portion thereof and the protective film 1 overlying the glass beads 2 are vertically connected together by a connecting wall 6 which is formed in a continuous network in a plan view dividing the surface of the sheeting into hermetically sealed cells 7, 7 of small areas.
  • This structure obviates the transparent focus layer 3 shown in FIG. 1 and, accordingly, it is not necessary to maintain uniformity of thickness of the focus layer 3. This remarkably contributes to improving of the angle characteristic of the reflex-reflecting sheeting.
  • the structure of the reflex-reflecting sheeting and the method for producing the same disclosed in the above publication may be summarized with reference to FIG. 2 as follows: First of all, upper hemispheres of glass beads 2 are embedded provisionally in a support layer (not shown) and a metallized layer 4, 4' is vapor-coated over the lower hemispheres of the glass beads 2 and the surface of the support layer which is not occupied by the glass beads 2. Then support film 5 made of thermoplastic polymer is coated on the metallized layer 4, 4' and a heat-resistant film 8 is provided under the support film 5 to cover the lower surface thereof.
  • the provisional support layer on the opposite side is stripped off and a biaxially-oriented transparent protective film 1 is laid over the upper hemispheres of the exposed glass beads 2.
  • the laminate is heated and pressed from the side of the heat-resistant film 8 by a platen having a network pattern of raised ridges represented by FIG. 3 or of a lattice work for forming desired isolated small cells 7, 7.
  • the support film 5 is partially melted to contact the transparent protective film 1 thereby forming the connecting wall 6 after the pattern of the platen which defines the isolated small cells 7.
  • the material and mechanical structure of the support film 5 must have not only sufficient strength and flexibility but also properties necessary for an adhesive, i.e., sufficient cohesive force within the material itself and sufficient adhesive force relative to the protective film 1.
  • thermosetting polymer may be used as the material for the support film, no specific example is given in the specification.
  • the reflex-reflecting sheeting disclosed in Japanese Patent Publication No. 7870/1960 adopted such structure that, as shown in FIG. 2 of the Publication, the metallized layer 4, 4' covers the lower hemispheres of the glass beads 2 and the portion which is not occupied by the glass beads 2 in an uninterrupted layer. That is to say, the metal deposit constitutes an integral and continuous surface.
  • a cover layer 9 of a bead-bond coating including a pigment such as a rutile type white pigment (TiO 2 ) as shown in FIG. 2 must be provided.
  • a pigment such as a rutile type white pigment (TiO 2 ) as shown in FIG. 2
  • TiO 2 rutile type white pigment
  • Japanese Preliminary Patent Publication No. 110592/1977 is a prior art directed to eliminate the above described drawback of the reflex-reflecting sheeting disclosed in Japanese Patent Publication No. 7870/1965, i.e., the inadequate durability due to utilization of a part of the support film of thermoplastic polymer as the connecting wall to the protective film.
  • this publication teaches that the adhesion of the support film to the protective film can be remarkably improved by employing a specifically selected composition for the main material of the support film, i.e., a special composition prepared by mixing into a mixture of acrylic-based thermoplastic polymer similar to the one disclosed in Japanese Patent Publication No. 7870/1965 ingredients such as monomer polyethylene glycol diacrylate, 2-cyanoethyl acrylate and 1,6-hexanediol diacrylate which are polymerized and cured by irradiation of ultraviolet ray, electron beam or heat ray.
  • a specifically selected composition for the main material of the support film i.e., a special composition prepared by mixing into a mixture of acrylic-based thermoplastic polymer similar to the one disclosed in Japanese Patent Publication No. 7870/1965 ingredients such as monomer polyethylene glycol diacrylate, 2-cyanoethyl acrylate and 1,6-hexanediol diacrylate which are polymerized and cured by irradiation
  • the above known sheeting may have sufficient adhesion in the interface of the support film and the protective film, strength of the portion of the connecting wall for connecting the support film with the protective film is not much different from the sheeting in which the thermoplastic support film is employed and besides strength inside the connecting wall is not necessarily sufficient.
  • breaking of the sheeting occurs not in the interface A of the support film material and the protective film but in the plane taken along line B-B' or the plane taken along line C-C' of the connecting wall 6.
  • the reflecting sheetings of the above prior arts exhibit remarkable shrinkage when heated. More specifically, when the support film materials, i.e., bonding materials disclosed in Japanese Patent Publication No. 7870/1965 and Japanese Preliminary Patent Publication No. 110592/1977, are utilized, the reflecting sheetings shrink significantly in the condition that the sheetings are permitted to stand for 3 hours in an atmosphere at 93° C. and then immersed in water for 21 hours, and such operation is repeated two or three times. Besides, at the higher temperature of 145° C., the protective film 1 is curled in about only 1 or 2 minutes and peels from the remaining portion, resulting in complete destruction of the sheeting.
  • the support film materials i.e., bonding materials disclosed in Japanese Patent Publication No. 7870/1965 and Japanese Preliminary Patent Publication No. 110592/1977
  • the production line after partial thermoforming of the support film be provided with a special apparatus such as ultraviolet or heat ray irradiating apparatus, and the support film be irradiated for a certain period of time after thermoforming of the connecting wall.
  • Examples 1-3, 5-10, and 12-14 of Japanese Preliminary Patent Publication No. 110592/1977 samples have been irradiated with a 190-kilovolt electron beam to a dose of 1.5 megarads by employing an electron beam irradiating apparatus, whilst in Example 4, the sheeting has been irradiated with ultraviolet rays using two passes at a rate of 50 ft./min. for curing the support film.
  • Example 11 the support film has thermally been cured by heating for 16 hours at 65° C. with the use of a heating device.
  • Preliminary Patent Publication No. 110592/1977 itself states in effect that such heat radiation for a long period of time is not desirable.
  • the support film is composed of an upper layer and a lower layer which have different compositions and physical properties from each other at least when the support film is adhered to the protective film such that the upper layer has larger adhesive force than that of the lower layer, whilst the lower layer has higher resistance to cohesive failure and rubbery elasticity than that of the upper layer, and the upper and lower layers are formed into the integral support film.
  • the object of the present invention can be attained more fully by adopting such a construction wherein the superfluous metallized layer is completely removed so that there is no requirement for a binder containing the pigment for shielding the metallized layer existing in a portion which is not occupied by glass beads.
  • the reflecting sheetings having the above described construction can be manufactured by the simple manufacturing method disclosed in Japanese Patent Publication No. 7870/1965 without requiring any special irradiating apparatus appearing in the technique disclosed in Preliminary Patent Publication No. 110592/1977.
  • FIG. 1 is a schematic sectional view showing an oridnary reflecting sheeting of a conventional type
  • FIG. 2 is a schematic sectional view showing a known reflecting sheeting of a capsule type
  • FIG. 3 is a schematic view showing the surface of the reflecting sheeting of FIG. 2;
  • FIG. 4 is a partly enlarged sectional view showing the reflecting sheeting according to the present invention.
  • FIG. 5 is a view showing an example of surface pattern constituting the connecting wall in the reflecting sheeting according to the present invention.
  • FIG. 4 An example of the construction of the finished sheeting prior to attaching a release paper thereto for delivery is shown in FIG. 4.
  • a protective film 1 is partially connected with a support film 5 by means of a connecting wall 6 formed by thermoforming of the support film 5.
  • the inside spaces surrounded by the wall 6 constitute hermetically sealed pockets or cells 7.
  • the lower hemispheres of glass beads 2 are embedded in an upper layer 5A of the support film 5, whereas the surfaces of the upper hemispheres thereof are exposed from the surface of the upper layer 5A in the cells 7.
  • the surfaces of the lower hemispheres of the beads 2 constitute a reflective surface covered with a metal vaporcoated film.
  • This structure is the same as that of the conventional capsule type reflecting sheetings.
  • the support film in the present invention must possess favorable adhesion to the protective film, and such adhesion is not determined one-sidedly by the principal component of the support film but depends upon relationship of the support film with the composition of the protective film.
  • One of the best combinations includes a combination of the protective film containing acrylic copolymer as the principal component and the support film containing acrylic-based polymer as the principal component.
  • the present invention is not limited to the above described combination, but any combination of the protective film made of a suitable polymer and the support film made of a crosslinked polymer may be utilized in the present invention.
  • the protective film comprises polycarbonate or polyvinyl chloride as the principal constituent and the support film comprises saturated polyester or linear polyurethane as the principal constituent can also be accepted.
  • the support film is made of a pasty material or by heating a thermoplastic material into a state in which the connecting wall can be formed. It should preferably be of a nature that it is crosslinked to cure at room temperatures before or after the formation of the connecting wall.
  • polyisocyanate whose crosslinking reaction proceeds at room temperatures be included in components of the support film, and a polymer having an active group such as OH group which reacts with polyisocyanate be employed as the principal constituent of the support film.
  • the support film in order to secure a sufficient internal strength of the thin connecting wall for connecting the support film with the protective film and prevent breaking inside the wall due to cohesive failure, is made of a combined structure comprising at least the upper and lower layers having different physical properties from each other.
  • composition of the upper layer of the support film should have good adhesion to the protective film and, at the same time, possess favorable affinity for the lower layer so that the upper and lower layers can be integrated together.
  • polymers constituting basic ingredients of these two layers are of the same type.
  • these polymers preferably are acrylic-based copolymers of the same tertiary or quaternary system polymers.
  • Viscosity of the support film at the time of thermo-forming thereof should be low for wetting sufficiently the protective film and the glass beads and thereby making the adhesion of the support film to the protective film favorable and increasing the strength of the resulting sheeting in the plane taken along line B-B' of FIG. 2.
  • the support film stretches with a result that the portion taken along line C-C' of FIG. 2 is thinned and the finished sheeting is apt to be broken here. This is the disadvantage of this type of prior art reflecting sheetings.
  • the inventor of the present invention has found that improvement of reflecting sheetings can be effectively attained by forming the support film by integral layers comprising at least the upper and lower layers having different properties from each other. More specifically, an important characteristic feature of the present invention resides in that the upper layer 5A of the support film 5 is made of a material having such composition that the viscosity thereof is low at the time of thermoforming, whilst the lower layer 5B is made of a material having such composition that it scarcely flows at the time of the thermoforming, and these materials having such different properties from each other are integrally combined with each other to form the support film.
  • the upper and lower layers of the support film having such construction as described above should preferably not have the quite same compounding ingredients. Namely, a material having a good wetting property relative to the protective film during thermoforming should be used for the upper layer material, whilst another material exhibiting large resistance to cohesive failure and large rubbery elasticity (JIS K6200) and, accordingly, having large stress against an external force and having tendency to rapid elastic restoration to the original state should be used for the lower layer.
  • JIS K6200 large resistance to cohesive failure and large rubbery elasticity
  • the upper layer performs the function of a cushion readily following expansion and contraction of the protective film whereas the lower layer performs the function of restricting the expansion and contraction of the upper layer to the minimum by virtue of the rubbery elasticity thereof whereby rupture of the connecting wall is effectively prevented.
  • a copolymer which is the basic ingredient contains an active group which is to react with isocyanate or the like.
  • the active group may be contained in a smaller amount in the upper layer than in the lower layer so that the degree of cure or degree of crosslinking in the upper layer during adhesion to the protective film may be reduced.
  • the adjustment of the degree of cure may conveniently be effected by adjusting the amount of a monomer including OH groups such as dihydroxymethyl methacrylate to be added to a mixture of monomer ingredients such as methyl methacrylate, ethyl methacrylate, butyl methacrylate which constitute a copolymer as the material of the upper layer in the support film, i.e., by making the amount of the former monomer in the upper layer smaller than that in the lower layer.
  • a catalyst for accelerating reaction of polyisocyanate may be included in the materials for forming the lower layer, or polyisocyanate of faster reaction may be used in the lower layer.
  • the support film as described above may be constructed in such a manner that a material film which forms the upper layer in the support film is first pushed against the surfaces of lower hemispheres of glass beads which have been metallized to have the lower hemispheres of the beads embedded substantially and then a lower layer film is laminated to the upper layer.
  • the upper layer film may be previously laminated to the lower layer film and then the resulting laminates may be pushed against the glass beads.
  • the upper layer of the support film should have thickness sufficient for completely embedding substantially the lower hemispheres of the glass beads, while the lower layer should be sufficiently thinner than the upper layer.
  • a support film which is formed by coating a material on a base film which does not firmly adhere to the support film or on a base film with a suitable releaser layer provided in between the support film and the substrate polymer film.
  • the support film comprising the upper and lower layers as mentioned above need not necessarily have a laminated structure which can be perfectly distinguished from each other but the interface of the two layers may rather be in such condition that it cannot be clearly distinguished.
  • the protective film should not be made of homopolymers of polymethyl methacrylate or polycarbonate. Films of these materials have been found unsuitable as the protective film for the construction of the reflecting sheetings according to the present invention. Furthermore, contrary to the general knowledge prevailing in the art, it has also been found unsuitable for the protective film of the reflecting sheetings that the films made of these materials are biaxially oriented. It has been confirmed by the inventor of the present invention that the film made of biaxially oriented polymer readily peels from the connecting wall formed by a part of the support film or causes cohesive failure in the connecting wall when the reflecting sheeting is exposed to a relatively high temperature.
  • a biaxially oriented polymethyl methacrylate film which has heretofore been practically utilized should not be employed as the protective film in the present invention. It is desirable to use, if possible, copolymers which are prepared by copolymerizing acrylic copolymers and synthetic rubber, Cellosolve acetate butyrate, styrene or the like, or a mixture of a part or all of these materials. In short, it is desirable to utilize a material which is stronger and more stretchable than a homopolymer of polymethyl methacrylate.
  • the support film of the present invention it is not sufficient for the support film of the present invention to have favorable thermal adhesion to the protective film but attention should be paid so that internal failure will not occur in a connecting wall portion for connecting the support film and the protective films to each other for defining small hermetically sealed cells between the two films.
  • the support film material according to the present invention which does not contain a photosensitive monomer has less tendency to deterioration due to light than materials containing such photosensitive monomer, but strength reduction due to temperature change and moisture absorption must be further taken into consideration.
  • a thin connecting wall of continuous lines for connecting the support film with the protective film is formed by thermoforming the support film in a reflecting sheeting wherein surfaces of the lower hemispheres of glass beads as well as the surface of the support film exposed in portions between the respective beads are covered with a metallized layer without a gap, metal deposits separated from the surface of the support film as well as a considerable number of metallized glass beads are included in the above thin connecting wall.
  • the inside of the thin wall of continuous lines is apt to be weakened due to internal strain caused by temperature change and moisture absorption to which the reflecting sheeting is subjected.
  • Methods for preventing retention of the metallized layer on the surface of the upper layer 5A of the support film in the portion not occupied by the glass beads include one in which the beads are first supported by a provisional support in the known manner, the beads thus supported are subjected to the metallizing step, a polymer having comparatively good adhesive force with respect to the provisional support and the metallized layer whilst having comparatively weak adhesive force with respect to the support film is then coated on the provisional support in a thin layer, thereafter the support film is provided thereon, and then the provisional support and the above stated polymer layer which has been coated thereon are peeled off together from the support film. Whatever the method may be, it must be one in which the provisional support and the metallized substance thereon do not directly contact with the support film.
  • one or more among several components to be copolymerized in a material used for the support film have active groups, chain molecules having a number of active groups are produced by the copolymerization of these components, and these chain molecules are crosslinked as a whole by polyisocyanate.
  • the support film Since the connecting wall is composed of a part of the support film, the support film must possess both cushioning properties which are required for the support film and strength which is required for the connecting wall. In this respect, it is very difficult to satisfy such requisites by the use of a monolayer film of a single component. Accordingly, the upper layer of the support film should be made different from the lower layer thereof in their compositions and physical properties so that a compounding exhibiting favorable adhesion to the protective film is selected for the former, whilst a compounding suitable for maintaining strength is selected for the latter. Remarkable improvement can be achieved by such structure of the support film. Further, if possible, separated metal deposits which are disadvantageous both for preventing cohesion failure and for appearance should be removed from the connecting wall.
  • setting type resin materials are utilized and cold-setting isocyanate-based components may advantageously be used for improving adhesion of the support film to the protective film and beads as well as to a metallized component included in the connecting wall and also for simplification of the operating steps.
  • Example 1 a support film formed by crosslinking acrylic-based compositions with polyisocyanate and thereby curing them and a protective film containing an unstretched (unoriented) acrylic-based copolymer as the principal constituent are employed.
  • the protective film 1 has a thickness of about 80 ⁇ m, and glass beads 2 each having 1.92 refractive index and 50-60 ⁇ m diameter are scattered with a ratio of 140 g/m 2 .
  • a metallized layer 4 on the lower hemispheres of the glass beads is formed by means of vacuum metallizing of metallic aluminum, whilst no metallized film exists on the surface of the support film 5.
  • the respective compositions of the upper layer 5A and the lower layer 5B of the support film 5 are as indicated in the columns of Example 1 in the following Table 1 and the corresponding columns in the list of material ingredients of the following Table 2, and a thickness of the upper layer is about 80 ⁇ m, while a thickness of the lower layer is about 30 ⁇ m.
  • a method for making the reflecting sheeting is substantially the same as that of the aforementioned prior art, so that the explanation therefor will be omitted in order to avoid repetition except for the following supplementary explanation.
  • the glass beads which are scattered on the provisional support and the lower hemisphere portions of which are covered with a metallized layer are then coated with a material which becomes the upper layer 5A of the support film 5.
  • the so coated provisional support is dried at 60° C. for 5 min. and further at 90° C. for 5 min.
  • the provisional support thus dried is coated with a material which becomes the lower layer 5B of the support film 5.
  • the resulting provisional support is dried at 70° C. for 2 min. and further at 90° C. for 2 min.
  • a heat resistant film 8 is made of a saturated polyester film of about 15 ⁇ m, the laminating temperature of which is about 40° C.
  • a connecting wall 6 is pressed into shapes at 170° C. in accordance with the known method. The surface pattern formed by the connecting wall of continuous lines is as shown in FIG. 5.
  • Example 2 has essentially the same construction as that of Example 1 except that a compounding ratio of acrylate constituting the principal constituent of the upper layer 5A of the support film 5, a kind of polyisocyanate, and amounts of polyisocyanate as well as titanium dioxide differ from those of Example 1 as indicated in Tables 1 and 2.
  • glass beads 2 each having a diameter 40-50 ⁇ m are scattered over with a ratio of 130 g/m 2 , and a dry thickness of the upper layer 5A of the support film 5 is 100 ⁇ m, while a dry thickness of the lower layer 5B is 40 ⁇ m.
  • Example 3 a saturated polyester composition and a polycarbonate film are utilized for the upper layer 5A of the support film 5 and the protective film 1, respectively.
  • the ingredients constituting the upper layer 5A of the support film 5 and the compounding ratio thereof in the present example differ from those of Example 1 as indicated in Table 1, but other conditions are the same as Example 1.
  • drying conditions after coating the upper layer 5A of the support film 5 are 60° C. and 3 min. followed by 90° C. for 3 min., these periods being shorter than those of Example 1.
  • Example 4 has the same construction as that of Example 3 except that the upper layer 5A of the support film 5 is made of a linear polyurethane composition as indicated in Tables 1 and 2, amount of titanium dioxide added thereto is smaller, and a polyvinyl chloride film is used as the protective film 1 as indicated in Table 1.
  • the upper layer 5A of the support film 5 is made of a linear polyurethane composition as indicated in Tables 1 and 2, amount of titanium dioxide added thereto is smaller, and a polyvinyl chloride film is used as the protective film 1 as indicated in Table 1.
  • Example 5 has substantially the same construction as that of Example 1 as indicated in Table 1. However, the amount of the polyisocyanate in the lower layer 5B of the support film 5 is smaller than that of Example 1, and tertiary amine manufactured by Koei Kagaku Kogyo K.K. is added as its catalyst in an amount corresponding to 0.2% of the amount of polyisocyanate.
  • thermoforming temperature for forming the connecting wall 6 is 200° C.
  • polyisocyanate (Trade name "Takenate D-110N") manufactured by Takeda Yakuhin Kogyo K.K. or the like polyisocyanate having higher reactivity than those used in the above respective Examples may be utilized without employing the aforesaid catalyst.
  • the support film 5 is made of setting type polymer materials and has an integral structure comprising at least the upper and lower layers which are preferably different in the degree of crosslinking, and hence in resistance to cohesive failure and extensibility from each other and at the same time have affinity to each other.
  • the upper layer may be made of any material having better adhesion to the protective film and also better cushioning property for supporting beads than the lower layer, whilst the lower layer may be made of any material having a strength sufficient to withstand breaking inside the connecting wall.
  • the material for the support film need not necessarily be a cold-setting type polymer, but a material which is cured by heating or other conventional means may also be used. It is, however, necessary that physical properties of the upper layer during thermoforming differ from those of the lower layer. An additional thin layer may be interposed between the upper and lower layers.
  • the reflecting sheeting according to the present invention is of a construction wherein the support film comprises at least the upper and lower layers having different compositions and physical properties from each other and the protective film is made of an unoriented film, so that the resulting sheeting exhibits strong resistance to interface failure or cohesive failure in the connecting wall portion caused by the external force or deterioration due to aging and, in addition, the sheeting can prevent effectively occurrence of shrinkage and deformation due to heating.
  • the support film comprises at least the upper and lower layers having different compositions and physical properties from each other and the protective film is made of an unoriented film, so that the resulting sheeting exhibits strong resistance to interface failure or cohesive failure in the connecting wall portion caused by the external force or deterioration due to aging and, in addition, the sheeting can prevent effectively occurrence of shrinkage and deformation due to heating.
  • an unoriented film is utilized as the protective film, advantages derived are significant.
  • the reflecting sheeting according to the present invention exhibits favorable bonding of the protective film to the support film so that the sheeting has strong resistance against separation of the two films even under high temperatures in places of severe heat. For instance, when a conventional reflecting sheeting is left to stand at a temperature of 145° C. for 1-2 minutes, the protective film shrinks and peels off resulting in deformation to such a degree that the original shape can hardly be recognized. In contrast thereto, substantially no change is observed in the reflecting sheeting made according to the present invention.
  • Table 3 indicates results of a heat shrinkage test wherein each square sample of 100 mm ⁇ 100 mm was cut out from the sheetings in which the known thermoplastic support film and thermosetting support film supplied by Minnesota Mining and Manufacturing Company were used and from the sheetings made on experimental basis according to Examples 1 and 2 of the present invention, each cut out sample was bonded to an aluminum plate, and the sample was heated at 145° C. for 2 minutes.
  • Table 4 indicates results of a heat-water cycle test. More specifically, Table 4 indicates results of measurement of actual dimensions and a peel test made in respect of the sheeting in which the known thermosetting type support film was used and the sheetings made on experimental basis according to Examples 1 and 2 of the present invention after the following test were repeated for 3 days, in other words, 3 cycles.
  • the test was conducted in such a manner that each square sample of 100 mm ⁇ 100 mm was cut out from the prior art sheeting and the sheetings made according to the present invention, each cut out sample was bonded to an aluminum plate, the sample was heated at 93° C. for 3 hours, and then the heated sample was immersed in water of 20° C.
  • the support film material is cured at room temperatures so that no apparatus for effecting electron beam or ultraviolet ray irradiation or heat ray irradiation for a long period of time is required. It is also an advantage of the preferred embodiment that no particular step is required after thermoforming of the connecting wall.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Laminated Bodies (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Road Signs Or Road Markings (AREA)
  • Illuminated Signs And Luminous Advertising (AREA)
  • Surface Treatment Of Optical Elements (AREA)
US06/708,253 1984-03-15 1985-03-05 Cellular reflex-reflecting sheeting Expired - Lifetime US4653854A (en)

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JP59048201A JPH0617921B2 (ja) 1984-03-15 1984-03-15 セル状反射シート
JP59-48201 1984-03-15

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JP (1) JPH0617921B2 (pt)
AT (1) AT396845B (pt)
AU (1) AU558687B2 (pt)
CA (1) CA1246371A (pt)
CH (1) CH662985A5 (pt)
DE (1) DE3508701A1 (pt)
ES (1) ES296031Y (pt)
FR (1) FR2561168B1 (pt)
GB (1) GB2156274B (pt)
IE (1) IE56392B1 (pt)
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Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4990024A (en) * 1984-03-26 1991-02-05 Minnesota Mining And Manufacturing Co. Preformed polyurethane roadway-marking strip which is highly conformant to road surface roughness
EP0672920A4 (en) * 1992-10-23 1995-06-26 Nippon Carbide Kogyo Kk MANUFACTURING PROCESS FOR RETRORE-REFLECTIVE FILM.
EP0693697A2 (en) 1994-07-22 1996-01-24 Nippon Carbide Kogyo Kabushiki Kaisha A method for producing retroreflective sheeting
AU667973B2 (en) * 1992-12-16 1996-04-18 Minnesota Mining And Manufacturing Company Supported encapsulated-lens retroreflective sheeting
EP0714040A2 (en) * 1994-11-24 1996-05-29 Nippon Carbide Kogyo Kabushiki Kaisha Capsule type retroreflective sheeting
WO1996035970A1 (en) * 1995-05-11 1996-11-14 Minnesota Mining And Manufacturing Company Encapsulated lens retroreflective sheeting having thermoplastic polyurethane bonding layer
WO1997001118A1 (en) * 1995-06-22 1997-01-09 Minnesota Mining And Manufacturing Company Encapsulated-lens retroreflective sheeting
US5601915A (en) * 1994-03-18 1997-02-11 Nippon Carbide Kogyo Kabushiki Kaisha Retroreflective sheeting
WO1997019815A1 (en) * 1995-12-01 1997-06-05 Stimsonite Corporation Cellular retroreflective sheeting
US5714223A (en) * 1995-05-12 1998-02-03 Minnesota Mining And Manufacturing Company Retroreflective sheet and article having retroreflectiveness
US5754338A (en) * 1996-04-01 1998-05-19 Minnesota Mining And Manufacturing Company Structured retroreflective sheeting having a rivet-like connection
US5784197A (en) * 1996-04-01 1998-07-21 Minnesota Mining And Manufacturing Company Ultra-flexible retroreflective sheeting with coated back surface
US5820988A (en) * 1996-02-02 1998-10-13 Minnesota Mining And Manufacturing Company Use of a crosslinked polyurethane adhesive on a retroreflective sheeting
WO1998045735A1 (en) * 1997-04-04 1998-10-15 Minnesota Mining And Manufacturing Company Use of a crystalline bead bond layer in a retroreflective article
US5910858A (en) * 1996-04-01 1999-06-08 Minnesota Mining And Manufacturing Company Retroreflective sheeting with coated back surface
US5959775A (en) * 1997-12-23 1999-09-28 3M Innovative Properties Company Urethane/acrylate bead bond for retroreflective articles
GB2339711A (en) * 1998-07-21 2000-02-09 Swintex Fabric reinforced retroreflective assembly
US6110574A (en) * 1995-12-12 2000-08-29 Nippin Carribe Kogyo Kabushiki Kaisha Retroreflective sheeting
US6303058B1 (en) 1996-06-27 2001-10-16 3M Innovative Properties Company Method of making profiled retroreflective marking material
US6586067B2 (en) 2001-04-02 2003-07-01 Avery Dennison Corporation Encapsulated lens retroreflective sheeting
US20040013856A1 (en) * 2002-04-18 2004-01-22 Yoshinori Araki Reflective articles and method of making
US6703108B1 (en) 1995-06-29 2004-03-09 3M Innovative Properties Company Wet retroreflective marking material
KR100463689B1 (ko) * 2001-11-21 2004-12-29 주식회사 엘지화학 우수한 내후성과 유연성을 갖는 역반사 시트 및 그의제조방법
CN106908887A (zh) * 2017-03-29 2017-06-30 宁波长阳科技股份有限公司 一种高亮度的涂布型反射膜
US10245812B2 (en) 2014-02-13 2019-04-02 3M Innovative Properties Company Dual cure stain resistant microsphere articles

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US4650283A (en) * 1984-08-03 1987-03-17 Minnesota Mining And Manufacturing Company Directionally imaged retroreflective sheeting
AU581288B2 (en) * 1985-03-01 1989-02-16 Minnesota Mining And Manufacturing Company Flat transparent top coat for retroreflective coating
US4664966A (en) * 1985-11-18 1987-05-12 Minnesota Mining And Manufacturing Company Enclosed-lens retroreflective sheeting having tough, weather-resistant, transparent cover film
CA1284141C (en) * 1985-11-18 1991-05-14 Minnesota Mining And Manufacturing Company Encapsulated-lens retroreflective sheeting and method of making
US4678695A (en) * 1985-12-23 1987-07-07 Minnesota Mining And Manufacturing Company Encapsulated flattop retroreflective sheeting and method for producing the same
JP2559476B2 (ja) * 1988-09-30 1996-12-04 ユニチカスパークライト株式会社 再帰性反射材の製造方法
GB2255313B (en) * 1991-04-09 1995-03-01 Swintex Retro-reflective assembly
JP2905102B2 (ja) * 1994-10-21 1999-06-14 紀和化学工業株式会社 再帰性高輝度反射シートの製造方法
US5759671A (en) * 1994-12-16 1998-06-02 Nippon Carbide Kogyo Kabushiki Kaisha Ultraviolet luminescent retroreflective sheeting

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US3836227A (en) * 1973-04-13 1974-09-17 Minnesota Mining & Mfg Heat-bondable retroreflective sheeting
US4023889A (en) * 1975-02-24 1977-05-17 Morgan Adhesives Company Retroreflective laminate
US4025159A (en) * 1976-02-17 1977-05-24 Minnesota Mining And Manufacturing Company Cellular retroreflective sheeting

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US4990024A (en) * 1984-03-26 1991-02-05 Minnesota Mining And Manufacturing Co. Preformed polyurethane roadway-marking strip which is highly conformant to road surface roughness
US5812316A (en) * 1992-10-23 1998-09-22 Nippon Carbide Kogyo Kabushiki Kaisha Method for making retroreflective sheeting
EP0672920A4 (en) * 1992-10-23 1995-06-26 Nippon Carbide Kogyo Kk MANUFACTURING PROCESS FOR RETRORE-REFLECTIVE FILM.
EP0672920A1 (en) * 1992-10-23 1995-09-20 Nippon Carbide Kogyo Kabushiki Kaisha Retroreflective sheet manufacturing method
AU667973B2 (en) * 1992-12-16 1996-04-18 Minnesota Mining And Manufacturing Company Supported encapsulated-lens retroreflective sheeting
US5601915A (en) * 1994-03-18 1997-02-11 Nippon Carbide Kogyo Kabushiki Kaisha Retroreflective sheeting
EP0693697A3 (en) * 1994-07-22 1998-06-03 Nippon Carbide Kogyo Kabushiki Kaisha A method for producing retroreflective sheeting
EP0693697A2 (en) 1994-07-22 1996-01-24 Nippon Carbide Kogyo Kabushiki Kaisha A method for producing retroreflective sheeting
EP0714040A2 (en) * 1994-11-24 1996-05-29 Nippon Carbide Kogyo Kabushiki Kaisha Capsule type retroreflective sheeting
US5601911A (en) * 1994-11-24 1997-02-11 Nippon Carbidekogyo Kabushiki Kaisha Capsule type retroreflective sheeting
EP0714040A3 (en) * 1994-11-24 1997-03-12 Nippon Carbide Kogyo Kk Sheet with encapsulated retro-reflective elements
CN1077496C (zh) * 1994-11-24 2002-01-09 日本电石工业株式会社 密封型定向反光片
US5784198A (en) * 1995-05-11 1998-07-21 Minnesota Mining And Manufacturing Company Encapsulated lens retroreflective sheeting having thermoplastic polyurethane bonding layer
WO1996035970A1 (en) * 1995-05-11 1996-11-14 Minnesota Mining And Manufacturing Company Encapsulated lens retroreflective sheeting having thermoplastic polyurethane bonding layer
US5714223A (en) * 1995-05-12 1998-02-03 Minnesota Mining And Manufacturing Company Retroreflective sheet and article having retroreflectiveness
WO1997001118A1 (en) * 1995-06-22 1997-01-09 Minnesota Mining And Manufacturing Company Encapsulated-lens retroreflective sheeting
US6703108B1 (en) 1995-06-29 2004-03-09 3M Innovative Properties Company Wet retroreflective marking material
WO1997019815A1 (en) * 1995-12-01 1997-06-05 Stimsonite Corporation Cellular retroreflective sheeting
US5930041A (en) * 1995-12-01 1999-07-27 Stimsonite Corporation Method of producing cellular retroreflective sheeting
US6110574A (en) * 1995-12-12 2000-08-29 Nippin Carribe Kogyo Kabushiki Kaisha Retroreflective sheeting
US5820988A (en) * 1996-02-02 1998-10-13 Minnesota Mining And Manufacturing Company Use of a crosslinked polyurethane adhesive on a retroreflective sheeting
US5754338A (en) * 1996-04-01 1998-05-19 Minnesota Mining And Manufacturing Company Structured retroreflective sheeting having a rivet-like connection
US5910858A (en) * 1996-04-01 1999-06-08 Minnesota Mining And Manufacturing Company Retroreflective sheeting with coated back surface
US5784197A (en) * 1996-04-01 1998-07-21 Minnesota Mining And Manufacturing Company Ultra-flexible retroreflective sheeting with coated back surface
US6303058B1 (en) 1996-06-27 2001-10-16 3M Innovative Properties Company Method of making profiled retroreflective marking material
WO1998045735A1 (en) * 1997-04-04 1998-10-15 Minnesota Mining And Manufacturing Company Use of a crystalline bead bond layer in a retroreflective article
US6156436A (en) * 1997-04-04 2000-12-05 3M Innovative Properties Company Use of a crystalline bead bond layer in a retroreflective article
US5959775A (en) * 1997-12-23 1999-09-28 3M Innovative Properties Company Urethane/acrylate bead bond for retroreflective articles
GB2339711A (en) * 1998-07-21 2000-02-09 Swintex Fabric reinforced retroreflective assembly
GB2339711B (en) * 1998-07-21 2002-07-31 Swintex Fabric reinforced retroreflective assembly
US6586067B2 (en) 2001-04-02 2003-07-01 Avery Dennison Corporation Encapsulated lens retroreflective sheeting
KR100463689B1 (ko) * 2001-11-21 2004-12-29 주식회사 엘지화학 우수한 내후성과 유연성을 갖는 역반사 시트 및 그의제조방법
US20040013856A1 (en) * 2002-04-18 2004-01-22 Yoshinori Araki Reflective articles and method of making
US10245812B2 (en) 2014-02-13 2019-04-02 3M Innovative Properties Company Dual cure stain resistant microsphere articles
CN106908887A (zh) * 2017-03-29 2017-06-30 宁波长阳科技股份有限公司 一种高亮度的涂布型反射膜

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IT1185062B (it) 1987-11-04
SE8501156D0 (sv) 1985-03-08
IT8519881A0 (it) 1985-03-13
CA1246371A (en) 1988-12-13
ES296031U (es) 1988-11-16
SE466523B (sv) 1992-02-24
FR2561168A1 (fr) 1985-09-20
GB2156274A (en) 1985-10-09
CH662985A5 (fr) 1987-11-13
IE56392B1 (en) 1991-07-17
DE3508701A1 (de) 1985-09-26
ATA73385A (de) 1993-04-15
DE3508701C2 (pt) 1990-10-18
AU3951985A (en) 1985-09-19
AT396845B (de) 1993-12-27
GB8505663D0 (en) 1985-04-03
SE8501156L (sv) 1985-09-16
AU558687B2 (en) 1987-02-05
IE850541L (en) 1985-09-15
FR2561168B1 (fr) 1989-03-17
GB2156274B (en) 1987-09-09
JPS60194405A (ja) 1985-10-02
ES296031Y (es) 1989-06-01
JPH0617921B2 (ja) 1994-03-09

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